Dynamic assembly of protein disulfide isomerase in catalysis of oxidative folding
Dynamic assembly of protein disulfide isomerase in catalysis of oxidative folding
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DOI：
10.1038/s41589-019-0268-8
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发表时间：
2019-05-01
影响因子：
14.8
通讯作者：
Inaba, Kenji
中科院分区：
文献类型：
--
作者：
Okumura, Masaki;Noi, Kentaro;Inaba, Kenji
对作用中的蛋白质进行时间分辨的直接观察为了解生物过程提供了必要的机制。在这里，我们介绍了蛋白质二硫异构酶（PDI）的作用机制，这是内质网中最通用的二硫引入酶，在氧化蛋白质折叠的催化过程中。高速原子力显微镜单分子分析表明，氧化后的PDI处于开放和封闭构象之间的快速平衡状态，而还原后的PDI则保持封闭状态。在未折叠底物存在的情况下，氧化的PDI，而不是还原的PDI，组装形成一个面对面的二聚体，形成一个具有多个氧化还原活性位点的中心疏水腔，在那里底物可能被容纳进行加速氧化折叠。这种PDI二聚体形状多样，并且根据底物具有不同的寿命。PDI根据自身的氧化还原状态和底物的构型或折叠状态调节构象动力学和寡聚物状态，有效地指导蛋白质正确的氧化折叠。
Time-resolved direct observations of proteins in action provide essential mechanistic insights into biological processes. Here, we present mechanisms of action of protein disulfide isomerase (PDI)-the most versatile disulfide-introducing enzyme in the endoplasmic reticulum-during the catalysis of oxidative protein folding. Single-molecule analysis by high-speed atomic force microscopy revealed that oxidized PDI is in rapid equilibrium between open and closed conformations, whereas reduced PDI is maintained in the closed state. In the presence of unfolded substrates, oxidized PDI, but not reduced PDI, assembles to form a face-to-face dimer, creating a central hydrophobic cavity with multiple redox-active sites, where substrates are likely accommodated to undergo accelerated oxidative folding. Such PDI dimers are diverse in shape and have different lifetimes depending on substrates. To effectively guide proper oxidative protein folding, PDI regulates conformational dynamics and oligomeric states in accordance with its own redox state and the configurations or folding states of substrates.